Attention and interest: a. What are some variables when it comes to attention?
b. What can we do when we need to pay attention to something that doesn’t hold our interest?
c. Is it possible to learn without attention? Without interest?

Suppose that three astronomical objects, 1, 2, and 3 are observed to lie on a line, and the distance from object 1 to object 3 is d. object 1 has four times the mass of object 3, and seven times the mass of object 2. find the distance between objects 1 and 2 for which the net force on object 2 is zero.